Fluid pressure governor



y 1950 E. R. FITCH 2,508,344

FLUID PRESSURE GOVERNOR Filed Aug. 13, 1948 Ellery RJ'p'l'clv.

Attorneys Patented May 16, 1950 UNITED STATES PATENT OFFICE FLUID PRESSURE GOVERNOR Ellery R. Fitch, Elyria, Ohio, assignor to Bendix- Westinghouse Automotive Air Brake Company, Elyria, Ohio, a corporation of Delaware Application August 13, 1948, Serial No. 44,107

12 Claims.

This invention relates to a fluid pressure control mechanism, and more particularly to a fluid pressure governor for controlling the operation of a compressor or pump in accordance with variations of pressure in the reservoir supplied by the compressor.

Various types of fluid pressure governors have heretofore been proposed in mechanisms of the above character. In one form which has been extensively employed, the desirable snap-action or kick-over has been obtained mechanically, so that utmost care and precision methods have been required in the manufacture in order to secure reliability of operation in service. Numerous other constructions have been utilized to secure the necessary snap-action but these have either presented complex manufacturing problems or have not been wholly satisfactory in operation throughout long periods of use.

It is accoordingly a principal object of the present invention to provide a fluid pressure governor so constituted as to avoid the objections and disadvantages of the governors heretofore utilized.

Another object of the invention is to provide a fluid pressure governor wherein the snap-action is obtained by a novel pneumatically controlled mechanism, thus avoiding the use of delicate operating parts and achieving an arrangement which may be economically manufactured.

A further object is to provide a governor of the above type which is so constituted as to insure positive operation at all times in accordance with variations in the pressure of the reservoir, in order to secure a reliable and efficient control of compressor operation.

"The above and other objects and novel features of the invention will appear more fully hereinafter from the following detailed description when considered in connection with the accompanying drawing wherein one embodiment of the invention is illustrated. It is to be expressly understood however, that the drawing is utilized for purposes of illustration only, and is not designed as a definition of the limits of the invention, reference being had for this purpose to the appended claims.

In the drawing; wherein similar reference characters refer to similar parts throughout the several views:

Fig. 4 is a sectional view taken substantially along line 4-4 of Fig. 1.

Referring more particularly to Figs. 3 and 4. the novel fluid pressure governor of the present invention is illustrated therein as including a body l having a connection l2 to a fluid pressure reservoir, and having also a connection 14 to a compressor unloading mechanism. The reservoir and unloader may be of any conventional form such as that shown for example, in the patent to B. S. Aikman No. 1,754,218 dated April 15, 1930, and hence have not been illustrated in the drawing herein. It will be understood that in systems of the type shown in the above patent, the governor operates to connect the reservoir to the compressor unloader when the reservoir pressure Fig. 1 is a bottom view of a fluid pressuregovernor constructed 'in' accordance with the "princlples of the present invention;

Fig. 2 is a side view of the governor;

reaches a pedetermined maximum, to unload the compessor. On the other hand, when the reservoir pressure drops to a predetermined minimum, the governor functions to disconnect the compressor unloader from the reservoir and reconnect it to atmosphere in order to load the compressor and permit the latter to replenish the fluid in the reservoir.

More particularly, the body i0 includes upper and lower body portions l6 and I8 having a diaphragm 20 clamped therebetween' as by means of a plurality of screws 22, the diaphragm and body portions forming an exhaust chamber 24 and a pressure chamber 26. The exhaust chamber 24 communicates at all times with the atmosphere through an opening 28 while the pressure chamber 26 communicates at all times with the reservoir connection l2 by way of connected ducts 30 and 32 formed in the lower body portion l8. As shown, the duct 32 is sealed from the atmosphere by a nut 34 and preferably a strainer 36 is positioned within the duct in order to prevent the entrance of dust and dirt to the governor.

In order to control the flow of fluid pressure from the governor to the unloader connection 14, a novel valve construction is employed, positioned in the upper body portion 16 and arranged to be operated by movement of the diaphragm 20. In the form shown such valve construction includes a valve assembly 38 having interconnected inlet and exhaust valves 40 and 42, the former valve being positioned in an inlet chamber 44 connected with the duct 32 bypassageways 4B and 48, and the latter valve being positioned within an outlet chamber which communicates at all times with the unloader connection I4 by way of ducts 52 and 54. The valve 38, in the position shown, is resiliently urged by a spring 56 so that --Fig. 3 is a sectional view taken substantially the inlet valve 40 is closed on a seat 58 in order alonglline 3-.-,-3 of Fig. 1, and

.7 to interrupt communication between the inlet and outlet chambers 44 and 50. At the same time, the outlet chamber 50 is connected with the exhaust chamber 24 through the open valve 42 and a hollow valve operating element 58 having an opening fill in the wall thereof, the upper part of this element forming a valve seat for the exhaust valve 52 i and being" constantly urged downwardlybya SpringfiZ. Thus this arrangement provides a communication to atmosphere the diaphragm causes a complete opening of the inlet valve 40, with a snap-action, in order to supply full reservoir pressure to the unloader connection to promptly unload the compressor. As one example, in actual practice, unloading of the compressor occurs when the reservoir pressure reaches about. one hundred ponnds per square inch;

After the compressor has been unloaded, as defor the unloader connection IA by way of ducts-.191 scribed above, no further fluid pressure will be 54 and 52, outlet chamber 59, open exhaust valve. 42, the hollow valve operating element 58;"opening 60, exhaust chamber -24.-r.ands.openinge 21%. Under these conditions, theuco-mphessor-will operate in a loaded condition in order *to-supply fluid pressure to the reservoir andtoqthereser-t; voir connection [2 of the governor.

A novel arrangement is provided by the present invention for operating the valve 38 in order to secure.- .the:..desir.able snap-action .or kick-lover of the governor. As shown such lmeans includes-a piston 64 whichis-securely.clamped tos-theldiaphragm 2 ll vbyaanut..$ 5; the .upper endofi the; pistonabutting the lowerend .otithevalve operating. element 58,'.and.. ther-.lower.; end of. the piston. being. constantly..urg.eddownwardly. byan ad-. justing... spring .fifltspositionedn within 1 a control. chamber. 6 as. The tensionroi the. springafifilmay. be. readily adjustedbil. meanspi. ac nut] asinorder. to;.. vary the, setting v,oii. thegovernoru. Preer..-. ablyla pairofiollowenplates .121 and..|4: are. dis: posedaom opposite. sides..of Lthe.cliaphrzugm 2 ill and are adapted .tQensage stops Clem-J 8. t0 -1lmll1 17he. travel o;the...diaphragm,in opposite. directions. Itwill ;be-observed;that.the 116513011154 is..slidably mounted-within. theuppercpart .of. the. lower .body. portion, l 8 land ,a suitable seaLBflzis proyidedin order-.. toprevent i any; leakage: of fluid pressure betweenthe. .chambers- .25..and 69l Chamber G9. communicatescat alltimes withthe hnloader con: nection .l it-by wayxofi .ducts e82. andj lr.

. Thesoperation otthe governor;..here.tofore.dee scribed is as follows. When;the;-1.compressor is.

star ed,..the;pnessure.in the reserlvoir-andcin the pressurecchamben 25 will...gradua-lly.. increase; to; anPDiIlt...WhGllGg theepressure mending. tocmovesthe diaphra ml hupwardly: is. .Sufiicient'to; overcome. the-tensionoflsprings 6 8;.andrfi 2. .Thereupon the diaphraemfini willnmovel upwardly, and throu h;

theacooperation .between...the. .uppel=; .end; of, the.: P15120111 6.41am the;-lower;endsof the-valve operatin elementjll ,the latter will hemmed-upwardly to contactthe. exhaust valveAZand closemommuni: catiombetween the .unloader.;connection. l4. and. the. exhaust; chamber-r 24s. Continued. upward movement;.of.thesalo velnamed parts-will thereaftermovethe valvezeerupwardly tO 0pn,th.9. I1.-:. let valve. 451.- a. slight amount...in .order, torinterr. connect the.reservoinconnection- J 2sandthe .u-nloaderconnectionl s..by .way;of..ducts;32-, 48 and; chamber .44; openinlet rvalve; 58,;outlet chamber. 55, .an.d.-d -ucts. gfizland; 54,; 7

When. the. 'lnletvalve issinitially slightlyopened and. the reser.voir..;,and;.unloaderL connections. are interconnected, as above indicateddt gwill beseerr thatsthe controlphamber, 6 9..is also supplied;with. fl-uid pressurebycreason ofethe duct flztconnecte ins; the control -chambergwith -thesduct. as. As

soon. as thissoccur rthes entire area.of-. the- -piston 64; is: subjected: to thecfluidi.pressurehwithin -.the control chamber. 6 9: .to suddenly {supplement the force acting upwardlylonttheldiaphragm. 2 ll Such additional force: will: prompt-lyhmovel the. dia

contacts;the-.-sto.p 16;: This :sudden: movement 05 supplied to the reservoir, and the pressure in the latter will decrease, either through leakage or by use pt ther fluidtozactuate various devices which may-be==associated-with the fluid pressure system The pressuredn the pressure chamber 26 willlikewisedecrease and under the action of the springs. 56, 6 2 and 68, it will be readily understood-that the diaphragm 20, the valve actuating element 58 and the valve 38 will gradually move downwardlyitdbringz the zinletu valve-Ammo. contact with the seam 8.and'thus;interrupt: conmruni: cation :betweenrthetreservoir TCOI'HQ-QGHDU I 2.. and the.unloadenconnection |4.-. At; this time, the compressonwillstill .be in anzunloaded condition;

However, further downwardzmoyement ofigthe. diaphragm-2 9.: andethe;valveaotuatheaelement .58 will serve-rtolslightly opentherexhausti valve 42 (in; order toestablish communicationbetween the-.co n.-.. trol chamber :6 fliandutheeexhaustrhamberfz a. As.- soonasthisoccurs;theepnessurawvithin.thelcontrol; chamb en.:-6 9; .drcpse 110351181111 am;- extenti that the s rin s;.B2;and;.6B;are;eftective to suddenhip pem the; exhaustlvalvec 42;.with assnap-action, to a.-

WidBiQDBI'L' positiom; .Thisactiomresultsin an inn-.- mediateeexhaustinseoi 1711 .2 unloadersconxlection |4.togatmospherebx-waytot thelconneotions heretoiore; set; forth-.1 whereupon; thelcompressor is again loaded andwilllbe efllectivetoereplenishthe fluid ipressure; imthezreservoir; r. In.:.the.-example mentlonedeheretofoneeandencountened:imactual. pnacticeeloadm softthei compressors occurs when. thegreservpiripressure is.;in;:theeneighborhood of; eighty-five pounds per square inch. ltwilliibe; understood what; adiustmentrlotithee tension of sonnet-.68 emayrb. ir diJH1aefiieCb9dx by; removal. ofycap ficandadfiststment ofmutrl 01m. order; to vary: 17119:}31.e55111165.iBIILWhILQIIithfiEgQYBIIHOE1011 35 .inandloute arrangementrfon effiectively zcontrolliner. al.00111- pressor runloadingsmechanism. 1., The use got-1 the; combinedinletsand exhaustev alverassemblr 0M 2 insures. that both 1 valvesswill not ;.be esimultar. neously openzthusavoidmg.anyicontinuouscbleeda ing of air to the atmospherezeA iurtherznovet featuredneludes the sisepirtheefluidrpnessune superated: piston 64; which: functions tin :response; to reservoir JDITCSSHliBi-zttlrCfil-ASQ aisnan actingrmover. mentzof vthevalvefl azinrboth; .d-izsectienszof; opera-l tioni-.. Therr arram ementproposedr: is; relatively;

simple. irrconstruction;andiavoidsstheinserondelie caterand;complicated.partszs.

Imcertain instanceszit maaebmdesirablectojn: crease therateeof build-11113231112 'exhaustmgaot the; pressure within ztheccontrol chamber: easel that the desirable pressure changes imthisachamben' may take place1:witlrouicmateriallwaffeetingrthe pressurerim the iunloaderzconneetedz Mith'j;he:.cOJm-. nection M. In such event, a suitabictchokermaxi be: inserted-rincthe conneetiomi 4M1 theeline leadi-nciromsaid;connectionsto;thesum ader;-:.

Although a specificeembbdimemioi:theeinvene tion has beemilhistratede and -fdeseribed therein, it willb'e readilylunderstoodfbyithoseskilled it the art that various changes; may betmade -therelm withoutdeparting from the spirit of the invention Reference will therefore be had to the appended'claims, for a definition of the limits of the invention. 4

What is claimed is: .7 i

1. A fluid pressure governorhaving a casing provided with a reservoir connection, an unloader connection and an atmospheric connection, valve means normally effective to establish communication between the unloader connection and the atmospheric connection and movableto interrupt said communication and establish communication between the unloader connection and the reservoir connection, and means for operating saidvalvemeans comprising a pair of connected pressureresponsive members, means for constantly subjecting one only of said members to the pressure of the fluid at the reservoir connection, and means for subjecting the other member to the pressure of the fluid at the reservoir connection only after movement of said valve means to establish communication between the unloader connection and the reservoir.

2. A fluid pressure governor having a casing provided with a reservoir connection, an unloader connection and an atmospheric connection, valve means normally effective to-establish communication between the unloader connection and the atmospheric connection and movable to interrupt said communication and establish communication between the unloader connection and the reservoir connection, and means for operating said valve means comprising a pressure responsive element having an operative connection with the valve means, said element forming with the casing, a pressure chamber, means to connect the pressure chamber at all times with the reservoir connection, a separate control chamber having a second pressure responsive element therein, said latter element being operatively connected with the first pressure responsive" element, and means to connect the control chamber to the reservoir connection only after movement of said valve means to establish communication between the unloader connection and the reservoir.

3. A fluid pressure governor having a casing provided 'with a reservoir connection, an unloader connection and an atmospheric connection, valve means normally eifective to establish communication between the unloader connection and the atmospheric connection and movable to interrupt said communication and establish communication between the unloader connection and the reservoir connection, and means for operating said valve means comprising a pair of separate chambers formed in said casing and having an apertured partition therebetween, a first pressure responsive member mounted in one of said chambers, a second pressure responsive member mounted in the other chamber and having a part extending through the aperture in the partition and in fluid sealing engagement with the walls thereof, means connecting said part to the first pressure responsive member, means to connect the one chamber at all times with the reservoir connection, and means to connect the other chamber to the reservoir connection only after movement of said valve means to establish communication between the unloader connection and the reservoir.

4. A fluid pressure governor having a casing provided with a reservoir connection, an unloaderconnection and an atmospheric connection, valve means normally effective to establish communication between the unloader connection and the atmospheric connection and movable to interrupt said communication and establish communication between the unloader connection and the reservoir connection, and means for operating said valve means comprising a diaphragm operatively connected with said valve means, a partition in said casing having an aperture therein, said diaphragm and partition forming a pressure chamber, means forming a control chamber in the casing and including said partition, a piston in said control chamber having a part extending through said aperture in fiuid sealing engagement with the walls thereof and being secured to said diaphragm, and means to connect the control chamber to the reservoir connection only after movement of said valve means to establish communication between the unloader connection and the reservoir.

5. A fluid pressure, governor having a casing provided with a reservoir connection, an unloader connection and an atmospheric connection, valve means normally eifective to establish communication between the unloader connection and the atmospheric connection and initially movable to a slightly open position to interrupt said communication and establish communication between the unloader connection and the reservoir connection, means including a first pressure responsive element constantly subjected to the fluid pressure at the reservoir connection for moving said valve means to said slightly open position, and means for suddenly moving said valve means to a fully open position comprising a second pressure responsive element operatively connected with the first pressure responsive element, and means controlled by movement of the valve means to said slightly open position to subject the second pressure responsive element to the fluid pressure at the reservoir connection.

5. A fluid pressure governor having a casing provided with a reservoir connection, an unloader connection and an atmospheric connection, a pair of connected pressure responsive members having different effective areas, a partition in said casing defining a pressure chamber with one of said members and coacting with the casing to define a separate control chamber for the other member, resilient means for constantly urging the members in one direction, means to constantly subject the pressure chamber to the fluid pressure at the reservoir connection, valve means normally effective to establish communication between the unloader connection and the atmospherlc connection and movable to interrupt said communication and establish communication between the unloader connection and the reservoir connection upon movement of said members in the opposite direction, and means for subjecting the other member to the fluid pressure at the reservoir connection upon movement of said valve means to establish said communication between the unloader connection and the reser-' voir connection.

7. A pressure responsive governor including a casing having an inlet chamber, an outlet chamber and an exhaust opening, interconnected inlet and exhaust valves for normally preventin communication between the inlet and outlet chambers and. for normally connecting the outlet chamber with the exhaust opening, a valve operating element movable in one direction to close the exhaust valve and to thereafter open the inlet valve, a pressure responsive member responsive at all times to the pressure in the inlet chamber for moving the element in said one direction BEDESWL the exhaustvalve andtothereatter. open thelinlet.

valve, a. pressure: responsive; member responsive at all; times;.to-. the. pressurein zthe :inletrchamber for moving the. element. inl-saide one; direction.

resilient means... for. .movinggntheeelement in .the 7 other. direction... a. seconda pressure, resp 0nsive member connectedwith the.first.named;..p 'essure responsive. membeumeans to;mount.said pressure responsive members, in separate chambers, .cooperatingmeans between thecasin andthe second pressure responsive. member. to. seal -.communication. between the chambers; and mea-nsto constantly. subject. the. second .pressure respgansivev member to. the. pressure in. the outlet chamber.

9. .A pressure responsive governor; including a casing haying an inlet chamber, .an outlet cham..- ber and an .exhaust.opening,,. interconnected inlet and" exhaust valves. for normally preventing com-. munication between the inlet and outletchambers and .for normally connecting -the outlet chamber with the exhaust opening, av valveroperating ele-. ment movable. in one. direction .to close. the; ex? haust .valveand to thereafter. open the inlet. valve, apressure. responsive member responsive-at. all timesto the. pressure: inthelinlet chamber vfor moving the element in said onedirection, resilient means for moving. theelementlin the other. direction, a second pressure. responsive member. .con-. nected with .the. first named pressure responsive member,v means to mount .sa'id pressurerespom sive members inseparate chambers, apartition between .said chambers and. having an...op ening therein, apart carried by saidsecond. pressure responsive member slidably positioned in: said opening and sealingcommunicationbetween said chambers by way of said opening, .and-meansto constantly subject the second pressure responsive member to the pressure, in .the. outlet chamber.

10. A fluid-pressure gomernor.having a..casing providedwith an inlet portcfor connection with. a reservoir. of fluid, pressure, an outletportfor connection with a compressor .unloader, andan atmospheric p rt, a pair. of connectedpressure responsive members within thecasing, said-meme bers having differentefiective areas and; cooperating with saidlcasing to defineapair-of separate fluidpressure chambers, resilientmeans fonconstantly; urging the membersin one direction, means for constantly connecting one-10f ,said. fluid pressure chambers withsaidinletport for. subjecting one of said members .at.all..times.to reservoir;pressure so that said members maybemoved in the opposite direction .when said. reservoir pres-:-

sure reaches a. predetermined .valuepa. valve nor.- mally effectiveltoestablish communication be: tween the outletand atmosp'heric ports. a. valve operating element operatively.connectedwith said onemember .foninterrupting. said. latter comm-u? nication when said. members are. moved. to apredetermined position and. meanslincluding arsece ondlvalve operablebymovement of.;said..membersbeyond :said; predetermined-position:forconnecting the other. fiuidxtpressure' chamber with .said inletz'portiandfor' connecting. the inlet and outlet ports.

11. A fluid pressure governor having; a-casing provided with;an inlet. port. for connection with a.:-reservoir;of.fluidbressure, an outlet port for connection. with .a' compressor unloader, and an atmosphericport; va1v.e.-means normally efiective for establishing communicationbetween the out-. let-portend the atmospheric; port and .movable to interrupt said. communication and establish communication. between-the outlet port and the inletiport; andmeans for movingsaid valve means comprisingv aadiaphragmmounted insaid casing tovprovidea first pressure chamber, a pressure responsive-member connected-with the diaphragm and .mountedin the casing to provide a second pressure chamber, .a passage for constantly cone nectingsaid first pressure chamber with the inlet port for subjecting the diaphragm at alltimes to..reservoir.pressure so that said, diaphragm and said pressure responsive member connected thereto. may be moved to move the ,valve means when saidcreservoir,:pressurereaches a predetermined value, and means to connectv the second, pressure chamberwith' the inlet port only after movement oftsaid rvalvemeans to establish said communica-q tion-betweenxthe outlet port andthe inlet port.

12. A..fiuid. pressuregovernor.having a casing provided. with an inlet port. for connection with a/reservoir of fiuidupressure, an. outlet port for connectionwith a. compressor unloader, and an atmosphericeport, a .pair. of connected pressure responsive: members within the. casing, said members .having different .efiectiveareas and cooperating-with said casingto define a pair of separate fluid pressure chambers, means for constantly connecting one-of said fluidPressure chambers withsaid. inlet portforsubjecting one of said membersat-all times to. reservoir pressure so that said membersmay bemoved inone direction in response to apredetermi-ned reservoir pressure, a valvermeans for controlling. communication between theou-tlet and atmospheric. ports,. and normally operable. to establish. communication betweentheou-tlet and atmospheric ports, an operating element for said. valve. means. operatively connected with saidione .member, resilientmeans for constantly; urgingthe member-sin the opposite direction. for. normally. maintaining. the. operating element .in-a position where. said. valve means is normally operable toestablish. communication betvveentheoutIet and atmospheric; ports, said element .beingmovablewith said one .member for interrupting. the latter. communication when said members are moved. in said .onedirection .to a predeterminedposition, anda second. valvemeans operable by ,movement. .of said membersv beyond said predetermined .positionfor connectii'ng, the other fluid. pressure .chamber with. saidinletport andior connecting the. inlet and outlet ports.

iELLERY R; FI'IECI-I.

REFERENEES CITE-D The ,following ref erences. .are of record-in the file. .of..this patent SZ'ILATESLJBAIENTS:

Number Name Date 1,871,535 Lattner Aug-p16; 1939 2,-292';294 Rotter; Aug. 4, 1942 '2',416-;855=" Sttclair Mar; 4,1947 2;420i3'70 Hamilton-i May 13, 194? 

